Sea snakes are not native or resident to Hawaii, meaning they do not maintain a permanent, breeding population in the surrounding waters. Hawaii has virtually no native snake species on land or in the sea, but strong oceanic currents occasionally carry a single species to the archipelago. When these reptiles appear, they are usually found washed ashore after being swept in from their normal open-ocean habitat.
The Yellow-bellied Sea Snake
The only sea snake species ever confirmed in Hawaiian waters is the Yellow-bellied Sea Snake (Pelamis platura), which is considered the most widespread snake species globally. This reptile is highly adapted to a fully aquatic, or pelagic, life, spending its entire existence floating and hunting in the open ocean. It is easily recognizable by its distinct coloration: a solid, dark brown or black top sharply contrasted with a bright yellow or brown bottom.
The body is laterally compressed, which assists in swimming, and it possesses a flattened, paddle-like tail that acts as a rudder for propulsion. Individuals typically reach an average length of 65 to 90 centimeters, though some can grow up to 1.1 meters. Because they are not strong swimmers, their presence in Hawaii is almost always transient, resulting from being passively carried by Pacific Ocean currents.
Venom, Temperament, and Safety
The Yellow-bellied Sea Snake possesses a potent venom that contains both neurotoxins and myotoxins, which can be lethal to humans. Fortunately, the snake is considered docile and non-aggressive toward humans, with bites being extremely rare.
The small mouth and short, fixed fangs make it difficult for the snake to deliver a significant dose of venom to a large target like a person. When defensive bites occur, studies suggest they often do not involve the injection of venom. State officials urge the public never to touch or harass any sea snake found in or near the water. It is strictly prohibited to import or possess any snake species in Hawaii, and sightings should be immediately reported to the state’s toll-free Pest Hotline.
Factors Limiting Permanent Establishment
Despite being present in the broader Pacific, the Yellow-bellied Sea Snake has not established a stable, breeding population in the Hawaiian archipelago. A major limiting factor is the reptile’s dependence on specific environmental conditions. Sea snakes breed in water temperatures above 20 degrees Celsius, but the Hawaiian Islands lack the necessary shallow, warm-water habitats for successful colonization.
This species is ovoviviparous, meaning it gives birth to live young directly at sea. Because the snake is poorly suited for movement on land, its body is tapered and lacks the broad belly scales of terrestrial snakes, making it helpless if washed ashore. Strandings are usually the result of strong winds and currents pushing the snakes out of their normal open-ocean environment.
Confusion with Other Marine Life
Most reported “sea snake” sightings in Hawaii are actually cases of mistaken identity involving marine eels. Hawaiian waters are home to numerous eel species, which have elongated, serpentine bodies that can easily be confused with a reptile.
The clearest way to distinguish them is that eels are fish and possess gills, a continuous dorsal fin, and no scales, meaning they never need to surface for air. In contrast, a sea snake is a true reptile with scales, no fins, and nostrils on top of its snout, requiring it to periodically surface to breathe air. The Yellow-bellied Sea Snake also has a distinct, solid black or dark upper side and a bright yellow underside, a pattern not shared by common Hawaiian eels.